Does Alcohol Help You Sleep Better?

Studies find that a nightcap can have both positive and negative effects.

Two topics I've written about on numerous occasions are the importance of sleep and the effects of alcohol on recovery. But there has always been a bit of confusion about how, exactly, the two interact. Anecdotally, alcohol is seen as something that helps you sleep, and some research confirms that – but other research finds that sleep quality can be disrupted. And a lot of the research is on alcoholics or people with other problems, which makes it hard to generalize.

There's a new systematic review in the journal Alcohol: Clinical & Experimental Research (press release here) that apparently consolidates all prior research on the effects of alcohol on sleep in healthy individuals. Sure enough, there's some good and some bad.

First the good. Alcohol does indeed reduce sleep latency at all doses – in other words, you're likely to fall asleep faster after a drink. Moreover, you're likely to get more "deep sleep," which is the period during which your body repairs and regenerates.

Sounds good – but there are caveats. Your body alternates between REM (rapid eye movement) and non-REM sleep in cycles of about 90 minutes. "Deep sleep" is a form of non-REM sleep – and, as mentioned above, it's the time when your body focuses on rebuilding tissue, bone, and muscle, and strengthens the immune system. But REM sleep (during which you dream) is also very important, moreso for your brain. The researchers describe the effects of REM as "defragmenting the drive" – getting too little affects memory and concentration. The problem is that while alcohol is boosting deep sleep, it's also reducing REM sleep.

The other big problem is that the good effects of alcohol on sleep (falling asleep faster and then getting more deep sleep) are restricted to the first half of the night; in the second half, you're more likely to wake up and sleep less deeply. As one of the researchers puts it: "(A)lcohol on the whole is not useful for improving a whole night's sleep. Sleep may be deeper to start with, but then becomes disrupted."

To me, that doesn't entirely rule out the usefulness of a nightcap in some situations. For some people getting to sleep can be a real challenge, and it sounds like alcohol can make it a little easier. But it's important to remember that (as always) there are trade-offs.